GF1 storing my pictures only 80% of the time

At random times, my brand new Lumix GF1 simply refuses to store the photo I just took on the memory card. The shutter clicks normally, but the photo never gets recorded, the card access icon does not blink, the photo does not get redisplayed, etc.

I can't find any pattern in when this happens: Sometimes I can take lots of pictures rapidly without problems. Sometimes it just skips one photo. At other times, I cannot store a picture for several minutes, then it works again. UPDATE: After hours of experimenting, it seems like photographing my computer screen works 99% of the time, but photographing my SanDisk packaging works 5% of the time - is the camera being selective about what it will store (which just sounds wrong to me)?

Basically the only thing I do is press the shutter button with the dial set to Intelligent Auto, so it is extremely frustrating that it does not just work. Am I missing something vital here (this IS my first semi-serious camera), or is the camera just performing completely unacceptably?

My initial suspicion was a memory card compatibility problem - but it is a new 32GB SanDisk Extreme SDHC Card, and both the card and the camera carry SDHC logos, and the manual says it handles 32 GB SDHC cards just fine. I also formatted the card using the camera, but it makes no difference.